If you want to lower your blood pressure -- and reduce your
risk of heart attack and stroke in the process -- a new study suggests you may want to get plenty of
sun.

Research published Jan. 20 in the Journal of Investigative Dermatology shows that light exposure has the ability to change a person's blood levels
of nitric oxide (NO), a signaling molecule that protects different organs. As nitric oxide levels increase, blood pressure drops, according to the researchers.

High blood pressure, or hypertension, occurs when there is too
much force pushing outwards on the walls of arteries, the American Heart Association
explains.

Arteries and veins carry blood to other parts of the body in order to
keep them functioning. Because arteries are made of muscles and semi-flexible
tissue, they have some stretch to them.

However, if the heart pumps the blood too
strongly, the arteries won’t snap back into place. This can be caused due to the buildup of cholesterol or plaque, or due to scarring from when
arteries were stretched too far in the past. Left untreated, high blood pressure can cause stroke, kidney damage, vision loss, erectile
dysfunction, memory loss, fluid in the lungs, peripheral artery disease and chest
pain.

Researchers exposed 24 participants to
ultraviolet A (UVA) light through tanning lamps during two 20-minute sessions. The amount of exposure was set to be about the same as
standing in the sun for 30 minutes in southern Europe. During one session, the participants got the full dose of heat and light from the lamps. The other time, they felt the heat but weren't subjected to the lighting.

When participants were exposed to UVA light, the
researchers saw their blood vessels dilate, their blood pressure drop and
the nitric oxide levels in their bloodstream increase. Vitamin D levels remained unchanged.

The decline in blood pressure was small, but significant
enough to show that the UVA exposure had made a difference, according to the researchers.

They found that the UVA rays specifically
affected nitric oxide molecules found in the upper layers of the skin and allowed them to be
released in the bloodstream. The results correlate with how blood pressure
changes throughout the seasons and why people have cardiovascular risk factors if they live in certain areas, the researchers added.

Blood pressure is typically higher in the winter and lower in the summer, the Mayo Clinic points out.

Study co-author Martin Feelisch, a professor of experimental
medicine and integrative biology at the University of Southampton, said the
study confirms that there are health benefits to getting some sunshine. Even
though excess sun exposure has been known to increase risk for skin cancer,
not getting enough sun may be detrimental to heart health. Vitamin D supplements
haven’t been able to provide all the same benefits as natural sunshine can, he said.

"We believe that NO from the skin is an important, so
far overlooked contributor to cardiovascular health. In future studies we
intend to test whether the effects hold true in a more chronic setting and
identify new nutritional strategies targeted at maximizing the skin's ability
to store NO and deliver it to the circulation more efficiently,” he said in a
press release.

But, senior study author Dr. Richard B. Weller, a dermatologist at
the University of Edinburgh in Scotland, told the New York Times that if
you have high blood pressure to begin with, just standing in the sun likely won’t cure
your woes.

“Getting sunlight is not enough if your blood pressure is
high. And if you have high blood pressure you need to get it controlled,” he
warned.